Control-flow restrictor
Jannik Pewny, Thorsten Holz · 2013
Runtime attacks that exploit software vulnerabilities are still an important concern nowadays. Even smartphone operating systems such as Apple's iOS are affected by such attacks since the system is implemented in Objective-C, a programming language that enables attacks such as buffer overflows. As a generic protection technique against a whole class of attacks, control-flow integrity (CFI) offers some interesting properties. Recent work demonstrated that CFI can be implemented on iOS by patching the binary during the loading process and adding an instrumentation layer that enforces CFI during runtime. However, this approach is of little practical value since it requires a jailbroken device, which hinders wide employment. Furthermore, binary patching has a certain performance impact.